Method for manufacturing toner

ABSTRACT

A method for manufacturing a toner including supplying powder particles containing a binder resin via a plurality of powder-particle supplying units to a treating chamber, the treating chamber having a cylindrical inner peripheral surface, heat treating the powder particles in the treating chamber by supplying hot air into the treating chamber, wherein a temperature of the hot air supplied into the treating chamber is 100.0° C. or higher and 200.0° C. or lower, and adjusting a humidity of the hot air so that a relative humidity of the hot air supplied into the treating chamber is 3.0% or more and 80.0% or less.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a method for manufacturing a tonerused for an image forming method such as an electrophotographic method,an electrostatic recording method, an electrostatic printing method, ora toner-jet-system recording method.

Description of the Related Art

In the image forming method of electrophotography, a toner fordeveloping an electrostatic image is used.

In recent years, in accordance with output materials or output images ofa copying machine or a printer having higher image quality and higherdefinition, performance required for a toner serving as a developingagent has become further severe. The toner is required to have a smallparticle diameter and a sharp particle size distribution wherein acoarse particle is not included.

Further, media for a copying machine or a printer have to also deal withvarious materials other than common paper, and an improvement in tonertransferability is also required. Consequently, demands for spheronizingthe toner have intensified.

However, on the other hand, if the toner is excessively spheronized,cleaning performance is reduced. Therefore, it is also required tocontrol a degree of spheronization of the toner so as to ensurecompatibility between the transferability and the cleaning performance.

To address such a demand, as a production method that controls thedegree of spheronization, there is a method in which the surface of thetoner is melted and spheronized by heat treatment.

In an apparatus for spheronizing a toner by heat treatment, toner ismelted by hot air and is spheronized. Therefore, when a balance betweenthe amount of the hot air supplied and the amount of the toner suppliedis lost, a toner having a predetermined degree of spheronization is notlimited to being obtained, or the apparatus is not limited to be stablyoperated since a molten toner melt-adheres inside the apparatus due toexcessive melting of the toner.

In addition, if the toner is not dispersed in the apparatus, tonerparticles melted by the hot air may adhere to and unite with each other,the particle diameter may increase, and a toner having predeterminedparticle diameter and degree of spheronization is not limited to beingobtained.

To address these disadvantages, a method for manufacturing a toner inwhich a toner having a predetermined degree of spheronization whilebeing in a state of a low cohesion degree is obtained by heat-meltingthe toner in a circulating stream of superheated seam is proposed(Japanese Patent Laid-Open No. 2008-129522). According to the proposal,it is disclosed that the cohesion degree of the toner is reduced, thetoner is readily spheronized, the production efficiency is high, and,further, the toner having excellent transferability is obtained.

However, when the toner is heat-treated by this manufacturing method,since the humidity of the superheated steam is high, condensation occursimmediately after contact with a low-temperature substance. Thecondensation may cause the toner to adhere inside the apparatus and theheated toner may melt-adhere inside the apparatus. In addition,regarding this manufacturing method, the speed of the toner-conveyingair is low, the toner is not sufficiently dispersed in the apparatus,united particles are generated, and a spheronized toner having apredetermined particle diameter is not limited to being obtained.

As described above, when the toner is spheronized by heat treatment, tosuppress toner melt-adhesion inside the apparatus from occurring, toreduce united particles, and to stably obtain the toner havingpredetermined particle diameter and degree of spheronization, there isroom for improvement in the heat-treatment apparatus and themanufacturing method for the toner.

SUMMARY OF THE INVENTION

The present disclosure suppresses powder particles from uniting witheach other and suppresses powder particles from adhering ormelt-adhering inside an apparatus so as to improve toner productivitywhen powder particles containing a binder resin is spheronized by heattreatment.

The present disclosure relates to a method for manufacturing a tonerincluding supplying powder particles containing a binder resin via aplurality of powder-particle supplying units to a treating chamber, thetreating chamber having a cylindrical inner peripheral surface, heattreating the powder particles in the treating chamber by supplying hotair into the treating chamber, wherein a temperature of the hot airsupplied into the treating chamber is 100.0° C. or higher and 200.0° C.or lower, and adjusting a humidity of the hot air so that a relativehumidity of the hot air supplied into the treating chamber is 3.0% ormore and 80.0% or less.

Further features of the present disclosure will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of connection of aheat-treating apparatus, a hot-air supplying unit, and ahumidity-adjusting unit.

FIG. 2 is a schematic perspective view illustrating an example of theheat-treating apparatus.

FIG. 3 is a schematic sectional view illustrating a cross section cutalong line III-III in FIG. 2 .

FIG. 4 illustrating a circulating member for spirally circulating hotair used in the heat-treating apparatus.

FIG. 5 is a schematic explanatory diagram illustrating a powder densityin accordance with the number of split when powders are supplied into atreating chamber.

DESCRIPTION OF THE EMBODIMENTS

The present disclosure will be described below in detail with referenceto a favorable embodiment.

The present disclosure relates to a method for manufacturing a tonerincluding heat-treating powder particles containing a binder resin byusing a heat-treating apparatus, wherein the heat-treating apparatusincludes (1) a treating chamber which has a cylindrical inner peripheralsurface and in which heat treatment by hot air is performed, (2) aplurality of powder-particle supplying units configured to supply thepowder particles to the treating chamber, and (3) a hot-air supplyingunit configured to supply the hot air that performs heat treatment intothe treating chamber, a humidity-adjusting unit configured to adjust ahumidity of a gas supplied to the hot-air supplying unit is connected tothe hot-air supplying unit, a temperature of the hot air when suppliedinto the treating chamber is 100.0° C. or higher and 200.0° C. or lower,and a humidity of the hot air is adjusted by using thehumidity-adjusting unit so that a relative humidity when supplied intothe treating chamber is set to be 3.0% or more and 80.0% or less.

In the present heat treatment, when the powder particles containing thebinder resin are spheronized, the temperature and the humidity of thehot air being adjusted enables powder particles to be suppressed fromuniting with each other and enables powder particles to be suppressedfrom adhering and melt-adhering inside the apparatus so as to improvethe productivity of the toner.

A mechanism thereof is conjectured that since the powder particles areheat-treated by the hot air humidified at the humidity in the rangeaccording to the present disclosure, the heat treatment is performed ina state in which an electrostatic adhesive power of the powder particlesis relaxed, and adhesion between powder particles and adhesion betweenthe powder particles and the apparatus are thereby reduced so as tosuppress melt-adhesion of the toner from occurring.

When powder particles unite with each other, since the shape of thetoner becomes an irregular shape, a temperature required for obtaining apredetermined circularity increases. In this regard, when a temperaturerequired for obtaining a predetermined circularity increases,melt-adhesion inside the apparatus tends to occur.

Adhesion between powder particles being reduced enables united particlesin the toner produced by heat treatment to be reduced and enables thetoner having a sharp particle size distribution to be produced. Inaddition, since adhesion or melt-adhesion of the toner to the apparatusbeing reduced enables the productivity of the toner to be improved andenables a time period required for stopping and cleaning the apparatusfor the purpose of maintenance of the apparatus to be reduced.

The outline of the heat-treating apparatus used in the presentdisclosure will be described with reference to FIG. 1 , FIG. 2 , FIG. 3, FIG. 4 , and FIG. 5 .

FIG. 1 is a diagram illustrating an example of connection of aheat-treating apparatus, a hot-air supplying unit, and ahumidity-adjusting unit. According to FIG. 1 , a gas that is taken intoa hot-air blower is taken into a humidity-adjusting unit in which thehumidity is adjusted, and the gas is supplied to the hot-air supplyingunit through the hot-air blower and a hot-air heater. Regarding thehumidity and the temperature of the hot air, the humidity and thetemperature immediately after the hot air passes through the hot-airsupplying unit are measured. The humidity-adjusting unit has to befollowed by the hot-air supplying unit, and the humidity-adjusting unitmay be disposed after the hot-air blower in FIG. 1 or may be disposedafter the hot-air heater.

There is no particular limitation regarding the humidity-adjusting unit,and a common humidity controller may be used. Examples include a steamtype humidifier, a vaporizing type humidifier, a fog type humidifier,and a hybrid humidifier in combination of these. Specific examplesinclude a gas type steam humidifier, an electrothermal steam humidifier,an electrode type steam humidifier, a vaporized fog type humidifier, avaporized steam type humidifier, a steam vaporizing type humidifier, anda centrifugal humidifier.

FIG. 2 is a schematic perspective view illustrating the heat-treatingapparatus. FIG. 3 is a schematic sectional view illustrating a crosssection cut along line III-III in FIG. 2 . FIG. 4 illustrates acirculating member for spirally circulating the hot air, which is usedin the heat-treating apparatus. FIG. 5 is a schematic explanatorydiagram illustrating a powder density in accordance with the number ofsplit when powders are supplied into a treating chamber.

As illustrated in FIG. 3 , the heat-treating apparatus includes acylindrical treating chamber 1 in which toner powder particles areheat-treated.

In the heat-treating apparatus, the shape of the treating chamber has tobe a cylindrical shape.

Further, the interior of the treating chamber can be cooled by using acooling jacket to prevent melt-adhesion of the powder particles fromoccurring. Cooling water (favorably an antifreeze such as ethyleneglycol) can be introduced into the cooling jacket, and the surfacetemperature of the cooling jacket can be 40° C. or lower.

In the heat-treating apparatus, powder-particle supplying units 2 and 10for supplying the powder particles to the treating chamber can bedisposed on the outer peripheral portion of the treating chamber. Inthis regard, the powder particles may be conveyed using the conveyingair so as to be supplied to the treating chamber or may be conveyed bysuction of a blower. When the conveying air is used, acceleration andconveyance may be configured to be performed by injection air suppliedfrom a high-pressure air-supplying nozzle (not illustrated in thedrawing).

The hot air for heat-treating the supplied powder particles is suppliedfrom a hot-air supplying unit 3. Regarding the hot air supplied into thetreating chamber, a temperature A (° C.) at an outlet portion of thehot-air supplying unit 3 is 100° C. or higher and 200° C. or lower. Thetemperature at the outlet portion of the hot-air supplying unit beingwithin the above-described range enables the powder particles to beprevented from melt-adhering and uniting due to the powder particlesbeing excessively heated and enables the powder particles to besubjected to uniform spheronization treatment.

When the temperature (° C.) is lower than 100° C., the powder particlesare not limited to being sufficiently spheronized. When the temperatureis higher than 200° C., since the treatment temperature is excessivelyhigh, melt-adhesion of the powder particles may occur inside theapparatus.

The relationship between the temperature A (° C.) of the hot air and theglass transition temperature Tg (° C.) of the binder resin of the tonercan be as described below. When the relationship between the hot-airtemperature and the glass transition temperature of the binder resin ofthe toner is as described below, heat-spheronization of the tonerparticle is efficiently performed. If the hot-air temperature is lowerthan the glass transition temperature of the binder resin of the toner,heat-spheronization of the toner particles tends to become difficult.

Tg≤A

The relative humidity of the hot air supplied into the treating chamberis adjusted to 3.0% or more and 80.0% or less by the humidity-adjustingunit and is adjusted to further preferably 4.0% or more and 75.0% orless.

When the relative humidity of the hot air supplied into the treatingchamber is within the above-described range, heat treatment is performedin a state in which an electrostatic adhesive power of the powderparticles to be heat-treated is relaxed. Consequently, adhesion betweenpowder particles and adhesion between the powder particles and theapparatus wall surface are thereby reduced so as to suppressmelt-adhesion of the toner from occurring.

Adhesion between the powder particles being reduced enables unitedparticles in the toner produced by heat treatment to be reduced andenables the toner having a sharp particle size distribution to beproduced. In addition, since adhesion or melt-adhesion of the toner tothe apparatus being reduced enables the productivity of the toner to beimproved and enables a time period required for stopping and cleaningthe apparatus for the purpose of maintenance of the apparatus to bereduced.

If the relative humidity of the hot air is less than 3.0%, since thehumidity of the hot air is low, the electrostatic adhesive power of thepowder particles to be heat-treated is not able to be reduced, andadhesion between powder particles and adhesion between the powderparticles and the apparatus wall surface are not limited to beingreduced. If the relative humidity of the hot air is more than 80.0%,condensation tends to occur inside the apparatus, condensation occurs onthe apparatus wall surface, and the toner may adhere and grow so as tocause melt-adhesion.

In the present disclosure, an absolute moisture content (g/m³) in thehot air supplied into the treating chamber is preferably 25.0 g/m³ ormore and 2,500.0 g/m³ or less and more preferably 590.0 g/m³ or more and2,200.0 g/m³ or less.

When the absolute moisture content of the hot air supplied into thetreating chamber is within the above-described range, an electrostaticadhesive power of the powder particles to be heat-treated is relaxed,and adhesion between powder particles and adhesion between the powderparticles and the apparatus wall surface are reduced so as to suppressmelt-adhesion inside the apparatus from occurring.

Further, in the present disclosure, an amount of the hot air suppliedinto the treating chamber is preferably 20.0 m³/min or more and 45.0m³/min or less and more preferably 30.0 m³/min or more and 45.0 m³/minor less.

In the present disclosure, when the amount of the hot air supplied intothe treating chamber is within the above-described range, since heattreatment is performed by using the hot air having humidity, anelectrostatic adhesive power of the powder particles is relaxed. Inaddition, shear force is generated due to a hot-air stream in thetreating chamber, and the powder particles are heat-treated in a highlydispersed state. Consequently, adhesion between powder particles andadhesion between the powder particles and the apparatus wall surface arereduced so as to suppress melt-adhesion inside the apparatus fromoccurring.

Further, in the present disclosure, a speed of the conveying air perunit of the plurality of powder-particle supplying units is preferably3.0 m/s or more and 12.0 m/s or less and more preferably 6.0 m/s or moreand 9.0 m/s or less.

In the present disclosure, when the speed of the conveying air is withinthe above-described range, the powder particles to be heat-treated inthe apparatus is highly dispersed due to the shear force of the airstream. The powder particles in a highly dispersed state being mixedwith the hot air enable the particles to be prevented from uniting witheach other and enable the particles having a high degree ofspheronization to be obtained.

Further, in the present disclosure, a relative humidity of the gasflowing in the treating chamber is preferably 95.0% or less and morepreferably 90.0% or less. The gas flowing in the treating chamber is agas mixture of all gases flowing in the chamber, such as the hot air,the cold air, and the conveying air, which are introduced into thecylindrical treating chamber, and secondary air and the like, which aretaken into the treating chamber with the conveying air. The relativehumidity of the gas flowing in the treating chamber is measured using ahygrometer disposed in a recovery unit 6 on a lower edge portion of thetreating chamber in FIG. 2 and FIG. 3 . The relative humidity of the gasflowing in the treating chamber being within the above-described rangeprevents condensation in the apparatus from occurring and reducesmelt-adhesion of the powder particles inside the apparatus.

The heat-treated powder particles are cooled by cold air supplied from acold-air supplying unit 4. The temperature (° C.) of the cold airsupplied from the cold-air supplying unit 4 can be −20° C. or higher and30° C. or lower. The temperature of the cold air being within theabove-described range enables the powder particles to be efficientlycooled and enables the powder particles to be prevented frommelt-adhering or uniting without impairing uniform spheronizationtreatment of the powder particles.

Regarding the powder particles supplied to the treating chamber, theflow thereof is regulated by a regulating unit 5, disposed in thetreating chamber, for regulating the flow of the powder particles.Consequently, the powder particles supplied to the treating chamber areheat-treated and, thereafter, cooled while circulating in the treatingchamber.

The cooled powder particles are recovered by the recovery unit 6 on alower edge portion of the treating chamber. In this regard, a blower(not illustrated in the drawing) is disposed downstream of the recoveryunit, and the blower is configured to suction and convey the powderparticles.

The regulating unit 5 for regulating the flow of the powder particlesused in the heat-treating apparatus is a columnar member having acircular cross section and is disposed on a central axis of the treatingchamber so as to protrude from the lower edge portion of the treatingchamber toward the upper edge portion. Since the regulating unit 5 forregulating the flow of the powder particles is disposed on the centralaxis of the treating chamber, the powder particles supplied to thetreating chamber flow in the cylindrical treating chamber whilecirculating.

The columnar member is provided with, at the central portion of theupper edge portion, a substantially cone-shaped distributing member 7for distributing the supplied hot air in the circumferential direction.The columnar member is further provided with a circulating member 8having blades 9 for spirally circulating the distributed hot air in thetreating chamber as illustrated in FIG. 4 .

When the hot-air supplying portion of the heat-treating apparatus hassuch a configuration, the hot air supplied from the hot-air supplyingunit flows in the cylindrical treating chamber while uniformlycirculating.

Consequently, the powder particles supplied into the treating chamberare heat-treated while receiving a centrifugal force due to acirculating flow. As a result, collisions between powder particles arereduced, and united particles of the powder particles during heattreatment are reduced.

To prevent the powder particles from melt-adhering, the columnar membercan include a cooling jacket. Further, cooling water (favorably anantifreeze such as ethylene glycol) can be introduced into the coolingjacket, and the surface temperature of the cooling jacket can be 40° C.or lower.

A powder-particle supplying unit 2 of the heat-treating apparatus isdisposed so that the circulation direction of the supplied powderparticles and the circulation direction of the hot air are the samedirection.

Since the circulation direction of the powder particles supplied to thetreating chamber is the same as the circulation direction of the hot airhaving humidity, a turbulent flow does not occur in the treatingchamber. Consequently, collisions between powder particles are reduced,an electrostatic adhesive power of the powder particles is relaxed, andthe humidity is uniformly delivered from the hot air to the powderparticles during heat treatment so that united particles and adhesioninside the apparatus are reduced, and melt-adhesion inside the apparatusis reduced.

The recovery unit 6 of the heat-treating apparatus is disposed on theouter peripheral portion of the treating chamber so as to maintain thecirculation direction of the circulated powder particles. Consequently,the circulating flow in the apparatus is maintained, the centrifugalforce applied to the powder particles is maintained, and adhesion andmelt-adhesion to the regulating unit 5 for regulating the flow of thepowder particles are reduced. Further, when this configuration isadopted, since introduced hot air, cold air, conveying air, and the likeare mixed in the recovery unit portion, constant humidity is maintained.

A plurality of cold-air supplying units 4 of the heat-treating apparatuscan be disposed on the outer peripheral portion of the treating chamber(4-1 to 4-3 in FIG. 3 ) so that the cold air supplied from the cold-airsupplying unit is supplied along the inner peripheral surface of thetreating chamber in the same direction as the circulation direction ofthe hot air.

The heat-treating apparatus has a configuration in which the cold airsupplied from the cold-air supplying unit is supplied from the apparatusouter peripheral portion to the treating chamber inner peripheralsurface in the horizontal and tangential direction so that the powderparticles are prevented from adhering to the treating chamber wallsurface.

The circulation direction of the cold air supplied from the cold-airsupplying unit being the same direction as the circulation direction ofthe hot air enables the powder particles to be prevented from unitingwith each other since a turbulent flow does not occur in the treatingchamber.

The cold air that is supplied can be split into a plurality of parts andintroduced on a horizontal cross section of the apparatus basis andoptionally can be split into eight parts and introduced. This intends tofacilitate uniform control of the air stream in the apparatus, and theamounts of the cold air in eight-part split introduction paths areindependently controllable. Consequently, the circulating flow in theapparatus is further enhanced, strong centrifugal force is applied tothe powder particles, and the dispersibility of the powder particles isimproved.

A plurality of powder-particle supplying units 2 of the heat-treatingapparatus can be disposed in the same circumferential direction so thatthe supplied powder particles are supplied along the inner peripheralsurface of the treating chamber.

The heat-treating apparatus has a configuration in which the powderparticles supplied from the powder-particle supplying unit 2 aresupplied from the apparatus outer peripheral portion to the treatingchamber inner peripheral surface in the horizontal and tangentialdirection. Consequently, strong centrifugal force is applied to thepowder particles supplied into the treating chamber, and thedispersibility of the powder particles is improved.

In the heat-treating apparatus, all the circulation directions of thepowder particles supplied from the powder-particle supplying unit, thecirculation direction of the cold layer supplied from the cold-airsupplying unit, and the circulation direction of the hot air having thehumidity supplied from the hot-air supplying unit are the samedirection. Consequently, a turbulent flow does not occur in the treatingchamber, the circulating flow in the apparatus is enhanced, strongcentrifugal force is applied to the powder particles, and,simultaneously, the humidity is uniformly delivered from the hot air tothe powder particles. As a result, an electrostatic adhesive power ofthe powder particles is relaxed, the dispersibility of the powderparticles is further improved, and a toner including reduced unitedparticles is obtained. In addition, since a turbulent flow does notoccur in the apparatus, adhesion of the powder particles to theapparatus inner wall is reduced, and melt-adhesion inside the apparatusis also reduced.

Further, in the heat-treating apparatus, a plurality of powder-particlesupplying units 2 are disposed in the same circumferential direction. Asillustrated in FIG. 5 , as the number of split of the powder-particlesupplying unit increases, the powder particles immediately after beingintroduced into the treating chamber are subjected to heat treatment inthe state in which a dust concentration is reduced. The humiditydelivered from the hot air to the powder particles becomes uniform withincreased number of split of the supplying unit. That is, as the numberof the powder-particle supplying unit increases, an electrostaticadhesive power is relaxed, and uniting and melt-adhesion are suppressedfrom occurring.

Next, the procedure of producing a toner by using the heat-treatingapparatus will be described.

In a raw-material mixing step, predetermined amounts of at least a resinand a coloring agent serving as toner raw materials are weighed andcombined, and mixing is performed. Examples of the mixing apparatusinclude Henschel mixer (produced by NIPPON COKE & ENGINEERING CO.,LTD.); SUPER MIXER (produced by KAWATA MFG. CO., LTD.); RIBOCONE(produced by OKAWARA MFG. CO., LTD.); NAUTA MIXER, TURBULIZER, andCyclomix (produced by Hosokawa Micron Corporation); Spiral Pin Mixer(produced by Pacific Machinery & Engineering Co., Ltd.); and LoedigeMixer (produced by Matsubo Corporation).

The mixed toner raw materials are melt-kneaded in a melt-kneading stepso as to melt the resins and disperse the coloring agent in the resin.Examples of the kneading apparatus include TEM Extruder (produced byTOSHIBA MACHINE CO., LTD.); TEX Twin Screw Extruder (Japan Steel Works,Ltd.); PCM Kneader (produced by Ikegai Machinery Co.); and KNEADEX(produced by NIPPON COKE & ENGINEERING CO., LTD.), and from theviewpoint of superiority of capability to continuously produce and thelike, continuous kneaders such as a single or twin screw kneader ratherthan a batch type kneader can be adopted.

Further, a colored resin composition obtained by melt-kneading the tonerraw materials is rolled using a two-roll mill or the like aftermelt-kneading and is cooled through a cooling step of performing coolingby water cooling or the like.

A cooled product of the colored resin composition obtained above ispulverized to a predetermined particle diameter in a pulverization stepthereafter. In the pulverization step, first, rough pulverization isperformed using a crasher, a hammer mill, a feather mill, or the like,and, fine pulverization is further performed using Kryptron System(produced by Kawasaki Heavy Industries Ltd.), Super Rotor (produced byNISSHIN ENGINEERING INC.), or the like so as to obtain toner fineparticles.

The resulting toner fine particles are classified into toner powderparticles having a predetermined particle diameter in a classificationstep. Examples of the classifier include Turboplex, FACULTY, TSPSeparator, and TTSP Separator (produced by Hosokawa Micron Corporation);and Elbow Jet (produced by Nittetsu Mining Co., Ltd.).

Subsequently, the resulting toner powder particles are subjected tospheronization treatment by using a heat-treating apparatus in a heattreatment step.

In this regard, before the heat treatment step, inorganic fine particlesand the like may be added to the resulting toner powder particles, asthe situation demands. In a method for adding the inorganic fineparticles and the like to the toner powder particles, predeterminedamounts of the toner powder particles and various known externaladditives are combined, and agitation and mixing are performed using ahigh-speed agitator such as Henschel Mixer, MECHANO HYBRID (NIPPON COKE& ENGINEERING CO., LTD.), Super Mixer, NOBILTA (produced by HosokawaMicron Corporation), or the like, which applies shear force to thepowder, as an external addition machine.

The inorganic fine powder being added to the toner powder particlesbefore the heat treatment step imparts fluidity to the toner powderparticles, enables the toner powder particles introduced into thetreating chamber to be more uniformly dispersed and to come into contactwith the hot air, and enables a toner having excellent uniformity to beobtained.

When a coarse particle is present after heat treatment, as the situationdemands, a step of removing the coarse particle through classificationmay be included. Examples of the classifier for removing the coarseparticle include Turboplex, TSP Separator, and TTSP Separator (producedby Hosokawa Micron Corporation); and Elbow Jet (produced by NittetsuMining Co., Ltd.).

Further, after the heat treatment, as the situation demands, to screen acoarse particle and the like, for example, screeners such as ULTRASONIC(produced by KOEI SANGYO CO., LTD.); Resonasieve and Gyro-Shifter(produced by TOKUJU CORPORATION); Turbo Screener (produced by TurboKogyo Co., Ltd.); Hi-BOLTER (produced by Toyo Hitec Co., Ltd.), and thelike may be used.

The heat treatment step may be performed after the above-described finepulverization or after the classification.

Next, toner constituent materials will be described.

Binder Resin

Common resins may be used as a binder resin used for a toner, andexamples include polyesters, styrene-acrylic acid copolymers,polyolefin-based resins, vinyl-based resins, fluorine resins, phenolresins, silicone resins, and epoxy resins. Of these, amorphouspolyesters can be used from the viewpoint of providing favorablelow-temperature fixability, and a low-molecular-weight polyester and ahigh-molecular-weight polyester may be used in combination from theviewpoint of ensuring compatibility between low-temperature flexibilityand hot-offset resistance. In this regard, a crystalline polyester maybe used as a plasticizer from the viewpoint of blocking resistanceduring storage and a further improvement in low-temperature flexibility.

Release Agent

Examples of the release agent used for the toner include the following.

Low-molecular-weight polyolefins, silicone waxes, fatty acid amides,ester waxes, carnauba waxes, hydrocarbon-based waxes, and the like areincluded. The release agents may be used alone, or at least two typesmay be used in combination.

When a binder resin used for producing a toner particle is synthesized,the release agent may be mixed with raw materials for synthesis of thebinder resin or may be added in a raw-material mixing step duringproduction of the toner. The release agent content in the toner can be 1part by mass or more and 20 parts by mass or less relative to 100 partsby mass of the binder resin.

Inorganic Fine Particles

As described above, the inorganic fine particles can be added to thetoner particle before the heat treatment step. The inorganic fineparticles serving as an external additive are mixed with the tonerparticles before heat treatment. The inorganic fine particles can befine particles of silica, titanium oxide, aluminum oxide, or strontiumtitanate. The inorganic fine particles can be hydrophobized using ahydrophobization agent such as a silane compound, a silicone oil, or amixture of these.

The number average particle diameter of the inorganic fine particles canbe 10 nm or more and 300 nm or less. To ensure compatibility betweenstabilization of durability and an improvement in fluidity, a pluralityof types of inorganic fine particles having a number average particlediameter within the above-described range may be used in combination.

The inorganic fine particle content can be 0.01 parts by mass or moreand 10.0 parts by mass or less relative to 100 parts by mass of thetoner particle.

Coloring Agent

Examples of the coloring agent used for the toner include the following.

That is, examples of the coloring agent include known organic pigmentsor oil-based dyes, carbon black, and magnetic materials.

Examples of the cyan-based coloring agent include copper phthalocyaninecompounds or derivatives thereof, anthraquinone compounds, and basic dyelake compounds.

Examples of the magenta-based coloring agent include condensed azocompounds, diketopyrrolopyrrole compounds, anthraquinone compounds,quinacridone compounds, basic dye lake compounds, naphthol compounds,benzimidazolone compounds, thioindigo compounds, and perylene compounds.

Examples of the yellow-based coloring agent include condensed azocompounds, isoindolinone compounds, anthraquinone compounds, azo metalcomplexes, methine compounds, and allylamide compounds.

Examples of black-based coloring agent include carbon black, magneticmaterials, and materials color-matched with black by using theyellow-based coloring agent, the magenta-based coloring agent, and thecyan-based coloring agent.

The coloring agents may be used alone, or at least two types may be usedin combination.

Next, methods for measuring various physical properties of the tonerparticles will be described below.

Method for Measuring Weight Average Molecular Weight (D4) of TonerParticles

The weight average molecular weight (D4) of the toner particles may becalculated on the basis of the measurement performed with the number ofeffective measuring channels of 25,000 and the analysis of themeasurement data by using an apparatus and software described below.

An accurate particle size distribution analyzer “Coulter CounterMultisizer 3” (registered trademark, produced by Beckman Coulter, Inc.)provided with a 50-μm aperture tube based on an aperture impedancemethodDedicated software “Beckman Coulter Multisizer 3 Version 3.51” (producedby Beckman Coulter, Inc.), attached to the above-described apparatus,for setting the measurement conditions and analyzing measurement data

Regarding an electrolytic aqueous solution used for the measurement, asolution in which analytical grade sodium chloride is dissolved intodeionized water so as to have a concentration of about 1% by mass, forexample, “ISOTON II” (produced by Beckman Coulter, Inc.) may be used.

Before the measurement and the analysis are performed, the dedicatedsoftware is set as described below.

In a “Changing standard operation method (SOM)” screen of the dedicatedsoftware, the total count number in the control mode is set to be 50,000particles, the number of measurements is set to be 1, and a Kd value isset to be a value obtained by using “Standard particles 10.0 μm”(produced by Beckman Coulter, Inc.). A threshold value and a noise levelare automatically set by pushing a “Threshold value/noise levelmeasurement button”. In addition, Current is set to be 1,600 μA, Gain isset to be 2, Electrolytic solution is set to be ISOTON II, and “Flush ofaperture tube after measurement” is checked.

In a “Setting conversion from pulse to particle diameter” screen of thededicated software, Bin interval is set to be logarithmic particlediameter, Particle diameter bin is set to be 256 particle diameter bin,and Particle diameter range is set to be 1 μm or more and 30 μm or less.

Specific measuring method is as described below.

(1) A 250 mL round-bottom glass beaker dedicated to “Multisizer 3” ischarged with about 200 mL of the electrolytic aqueous solution, thebeaker is set into a sample stand, and counterclockwise agitation with astirrer rod is performed at 24 rotations/sec. Subsequently,contamination and air bubbles in the aperture tube are removed by a“Flush of aperture tube” function of the dedicated software.

(2) A 100 mL flat-bottom glass beaker is charged with about 30 mL of theelectrolytic aqueous solution. To the beaker, about 0.3 mL of dilutedliquid prepared by diluting a dispersing agent “Contaminon N” (10% bymass aqueous solution of neutral detergent for precision measurementappliance cleaning which includes a nonionic surfactant, an anionicsurfactant, and an organic builder and which has a pH of 7, produced byWako Pure Chemical Industries, Ltd.) with deionized water by a factor of3 on a mass basis is added.

(3) An ultrasonic dispersion device “Ultrasonic Dispersion System Tetora150” (produced by Nikkaki Bios Co., Ltd.) that includes two oscillatorshaving an oscillation frequency of 50 kHz, with their phases shifted by180 degrees from each other, and that has an electrical output of 120 Wis prepared. A water tank provided with the ultrasonic dispersion deviceis charged with a predetermined amount of deionized water, and about 2mL of Contaminon N above is added to the water tank.

(4) The beaker according to (2) above is set into a beaker fixing holeof the ultrasonic dispersion device, and the ultrasonic dispersiondevice is operated. Subsequently, the height position of the beaker isadjusted so that the resonance state of the liquid surface of theelectrolytic aqueous solution in the beaker becomes at a maximum level.

(5) In the state in which the electrolytic aqueous solution in thebeaker according to (4) above is irradiated with ultrasonic waves, about10 mg of toner is added gradually to the electrolytic aqueous solutionand dispersed. Subsequently, the ultrasonic dispersion treatment iscontinued for further 60 sec. In this regard, during the ultrasonicdispersion, the water temperature of the water tank is appropriatelyadjusted to become 10° C. or higher and 40° C. or lower.

(6) The electrolytic aqueous solution, according to (5) above,containing dispersed toner particles is dripped to the round-bottombeaker, according to (1) above, set into the sample stand by using apipette so that the measured concentration is adjusted to about 5%.Subsequently, the measurement is performed until the number of measuredparticles reaches 50,000.

(7) The weight average particle diameter (D4) is calculated by analyzingthe measurement data with the dedicated software attached to theapparatus. In this regard, an “Average diameter” on an “Analysis/volumestatistical value (arithmetic mean)” screen, where graph/volume % is setin the dedicated software, corresponds to the weight average particlediameter (D4).

Method for Measuring Average Circularity

The average circularity of the toner particles may be measured with aflow particle image analyzer “FPIA-3000” (produced by SYSMEXCORPORATION) under the measurement and analysis condition of thecalibration operation.

The specific measuring method is as described below.

About 20 mL of deionized water, from which impurity solids and the likehave been removed in advance, is placed into a glass container. About0.2 mL of diluted liquid prepared by diluting a dispersing agent“Contaminon N” (10% by mass aqueous solution of neutral detergent forprecision measurement appliance cleaning which includes a nonionicsurfactant, an anionic surfactant, and an organic builder and which hasa pH of 7, produced by Wako Pure Chemical Industries, Ltd.) withdeionized water by a factor of 3 on a mass basis is added thereto.

Further, about 0.02 g of measurement sample is added, and a dispersiontreatment is performed for 2 minutes by using an ultrasonic dispersiondevice so as to prepare a dispersion liquid for the measurement. In suchan instance, cooling is appropriately performed so that the temperatureof the dispersion liquid becomes 10° C. or higher and 40° C. or lower.Regarding the ultrasonic dispersion device, a table top ultrasoniccleaner dispersion device (“VS-150” (produced by VELVO-CLEAR)) having anoscillation frequency of 50 kHz and an electrical output of 150 W isused. A predetermined amount of deionized water is placed into a watertank. About 2 mL of Contaminon N above is added to the water tank.

In the measurement, the above-described flow particle image analyzerincorporated with a standard objective lens (magnification of 10 times)is used, and a particle sheath “PSE-900A” (produced by SYSMEXCORPORATION) is used as a sheath liquid. The dispersion liquid preparedin the above-described procedure is introduced into the above-describedflow particle image analyzer, and 3,000 toner particles are measured ina total counter mode of the HPF measurement mode. The averagecircularity of the toner particles is determined, where the binarizationthreshold value in particle analysis is specified to be 85% and theanalysis particle diameter is limited to 1.985 μm or more and less than39.69 μm on an equivalent circle diameter basis.

In the measurement, automatic focusing is performed before start of themeasurement by using standard latex particles. Regarding the standardlatex particles, standard latex particles (“RESEARCH AND TEST PARTICLESLatex Microsphere Suspensions 5200A” produced by Duke ScientificCorporation are diluted with deionized water) are used. Thereafter,focusing can be performed every 2 hours from start of the measurement.

In the example according to the present disclosure, the flow particleimage analyzer subjected to calibration operation by SYSMEX CORPORATIONwas used, where a calibration certificate was issued. The measurementwas performed under the measurement and analysis condition on the basisof the calibration certificate except that the analysis particlediameter was limited to 1.985 μm or more and less than 39.69 μm on anequivalent circle diameter basis.

Measurement of Glass Transition Temperature (Tg) of Toner

The glass transition temperature is measured in conformity with ASTMD3418-82 by using a differential scanning calorimeter “Q2000 (producedby TA Instruments)”. The temperature calibration of the detection unitof the apparatus uses the melting points of indium and zinc, andcalibration of the heat quantity uses the heat of fusion of indium.

Specifically, about 3 mg of resin or toner particles are preciselyweighed and are placed into an aluminum pan, an empty aluminum pan isused for reference, and measurement is performed under the followingconditions.

Temperature rise rate: 10° C./minMeasurement start temperature: 30° C.Measurement completion temperature: 180° C.

The measurement temperature range is set to be 30° C. to 180° C., andthe measurement is performed at a temperature rise rate of 10° C./min.The temperature is once raised to 180° C., maintained for 10 min, anddecreased to 30° C. Thereafter, the temperature is raised again. Achange of specific heat is obtained in the temperature range of 30° C.to 100° C. during the second temperature rise. In this regard, anintersection point of a line passing through the midpoint of the baselines before and after an occurrence of change in the specific heat andthe differential thermal curve is taken as the glass transitiontemperature (Tg).

EXAMPLES

The present disclosure will be more specifically described below withreference to examples according to the present disclosure andcomparative examples. However, the present disclosure is not limited tothese examples. In the examples below, “part” is on a mass basis, unlessotherwise specified.

Production Example of Amorphous Polyester L

Polyoxypropylene(2,2)-2,2-bis(4-hydroxyphenyl)propane: 72.0 parts (0.200parts in a mole fraction; 100.0% by mole relative to a total number ofmoles of polyhydric alcohols)Terephthalic acid: 28.0 parts (0.169 parts in a mole fraction; 96.0% bymole relative to a total number of moles of polyvalent carboxylic acids)Tin 2-ethylhexanoate (esterification catalyst): 0.5 parts

The above-described materials were weighed into a reaction vesselprovided with a cooling tube, an agitator, a nitrogen introduction tube,and a thermocouple. After the interior of the reaction vessel wasreplaced with a nitrogen gas, the temperature was gradually raised underagitation, and a reaction was performed for 4 hours at a temperature of200° C. under agitation.

The pressure in the reaction vessel was decreased to 8.3 kPa andmaintained for 1 hour. Thereafter, cooling to 180° C. was performed, andthe pressure was returned to atmospheric pressure.

Trimellitic anhydride: 1.3 parts (0.007 parts in a mole fraction; 4.0%by mole relative to a total number of moles of polyvalent carboxylicacids)tert-butylcatechol (polymerization inhibitor): 0.1 parts

Subsequently, the above-described materials were added, the pressure inthe reaction vessel was decreased to 8.3 kPa, a reaction was performedfor 1 hour while the temperature was maintained at 180° C., and thereaction was stopped by decreasing the temperature after checking thatthe softening temperature measured in conformity with ASTM D36-86reached 90° C. so as to obtain Amorphous polyester L.

Production Example of Amorphous Polyester H

Polyoxypropylene(2,2)-2,2-bis(4-hydroxyphenyl)propane: 72.3 parts (0.200parts in a mole fraction; 100.0% by mole relative to a total number ofmoles of polyhydric alcohols)Terephthalic acid: 18.3 parts (0.110 parts in a mole fraction; 65.0% bymole relative to a total number of moles of polyvalent carboxylic acids)Fumaric acid: 2.9 parts (0.025 parts in a mole fraction; 15.0% by molerelative to a total number of moles of polyvalent carboxylic acids)Tin 2-ethylhexanoate (esterification catalyst): 0.5 parts

The above-described materials were weighed into a reaction vesselprovided with a cooling tube, an agitator, a nitrogen introduction tube,and a thermocouple. After the interior of the reaction vessel wasreplaced with a nitrogen gas, the temperature was gradually raised underagitation, and a reaction was performed for 2 hours at a temperature of200° C. under agitation.

The pressure in the reaction vessel was decreased to 8.3 kPa andmaintained for 1 hour. Thereafter, cooling to 180° C. was performed, andthe pressure was returned to atmospheric pressure.

Trimellitic anhydride: 6.5 parts (0.034 parts in a mole fraction; 20.0%by mole relative to a total number of moles of polyvalent carboxylicacids)tert-Butylcatechol (polymerization inhibitor): 0.1 parts

Subsequently, the above-described materials were added, the pressure inthe reaction vessel was decreased to 8.3 kPa, a reaction was performedfor 15 hours while the temperature was maintained at 180° C., and thereaction was stopped by decreasing the temperature after checking thatthe softening temperature measured in conformity with ASTM D36-86reached 137° C. so as to obtain Amorphous polyester H.

Crystalline Polyester

1,6-Hexanediol: 34.5 parts (0.29 parts in a mole fraction; 100.0% bymole relative to a total number of moles of polyhydric alcohols)Dodecanedioic acid: 65.5 parts (0.28 parts in a mole fraction; 100.0% bymole relative to a total number of moles of polyvalent carboxylic acids)Tin 2-ethylhexanoate: 0.5 parts

The above-described materials were weighed into a reaction vesselprovided with a cooling tube, an agitator, a nitrogen introduction tube,and a thermocouple. After the interior of the reaction vessel wasreplaced with a nitrogen gas, the temperature was gradually raised underagitation, and a reaction was performed for 3 hours at a temperature of140° C. under agitation.

The pressure in the reaction vessel was decreased to 8.3 kPa, and thereaction was performed 4 hours while the temperature of 140° C. wasmaintained.

The pressure in the reaction vessel was gradually released and returnedto atmospheric pressure. Thereafter, 7.0% by mole of stearic acid wasadded relative to 100.0% by mole of the raw material monomer, and areaction was performed at atmospheric pressure and 200° C. for 2 hours.

Subsequently, the pressure in the reaction vessel was decreased again to5 kPa or less, and the reaction was performed at 200° C. for 3 hours soas to obtain a crystalline polyester.

Production Example of Toner Powder Particles

Amorphous polyester L: 70 partsAmorphous polyester H: 30 partsCrystalline polyester: 5 partsFischer-Tropsch wax (peak temperature of maximum endothermic peak of 90°C.): 6 parts C.I. Pigment Blue 15:3:7 parts

After the materials of the above-described combination were mixed usinga Henschel mixer Model FM-75 (produced by NIPPON COKE & ENGINEERING CO.,LTD.), kneading was performed using a twin screw kneader Model PCM-30(produced by Ikegai Machinery Co.) at a temperature set to be 120° C.The resulting kneaded material was cooled and coarsely pulverized to 1mm or less by using a hammer mill so as to be made into a toner coarselypulverized material. The resulting toner coarsely pulverized materialwas pulverized using a mechanical pulverizer T-250 (produced by TurboKogyo Co., Ltd.) so as to obtain toner fine particles. The resultingtoner fine particles were classified using FACULTY (produced by HosokawaMicron Corporation).

In such an instance, the resulting toner powder particles had a glasstransition temperature of 58° C., a weight average particle diameter(D4) of 5.73 μm, and an average circularity of 0.952.

Hereafter, this is denoted as Toner powder particles A1.

Further, the following materials were placed into a Henschel mixer(Model FM-75, produced by NIPPON COKE & ENGINEERING CO., LTD.), andmixing was performed at a peripheral speed of the rotary blade of 50.0m/sec for a mixing time of 3 min so as to obtain Toner powder particlesB1 in which silica and strontium titanate adhered to the surface ofToner powder particles A1.

Toner powder particles A1: 100 partsSilica fine particles (number average particle diameter of 100 nm): 3partsStrontium titanate (number average particle diameter of 30 nm): 0.5parts

Example 1

In the present example, the humidity-adjusting unit was connected to thehot-air supplying unit, and Toner powder particles B1 was heat-treatedusing the heat-treating apparatus illustrated in FIG. 2 and FIG. 3 andthe circulating member illustrated in FIG. 4 , wherein the raw-materialsupplying unit was split into eight parts as illustrated in FIG. 5 ,under the following operation conditions.

Amount of Toner powder particles B1 supplied: 200 kg/hrHot-air temperature: 160.0° C.Amount of hot air: 35.0 m³/minHot-air relative humidity: 67.3%Hot-air absolute moisture content: 2085.0 g/m³Speed of conveying air per powder-particle supplying unit: 8.0 m/sRelative humidity of gas flowing in heat-treating apparatus: 90%

Regarding other operation conditions, the cold-air temperature was −5°C., and 6.0 m³/min of each of the first stage cold air and the secondstage cold air was split into eight parts so that 0.75 m³/min per partof cold air was supplied into the treating chamber. Further, 4.2 m³/minof the third stage cold air was split into three parts so that 1.4m³/min per part of cold air was supplied into the treating chamber.

The resulting heat-treated particles had a weight average particlediameter (D4) of 5.73 μm and an average circularity of 0.968.

In this regard, the cohesiveness of the resulting heat-treated particleswas evaluated as described below.

Evaluation of Cohesiveness of Heat-Treated Particles

A difference between the weight average particle diameter of theresulting heat-treated particles and the weight average particlediameter of Toner powder particles B1 before heat treatment (ΔD4=weightaverage particle diameter of heat-treated particles−weight averageparticle diameter of Toner powder particles B1) was calculated andevaluated in accordance with the following criteria.

A: ΔD4<0.10 B: 0.10≤ΔD4<0.20 C: 0.20≤ΔD4<0.30 D: 0.30≤ΔD4

Further, after the operation was performed for 1 hour under the sameconditions, melt-adhesion inside the apparatus was examined as describedbelow and evaluated.

Evaluation of Melt-Adhesion Inside Apparatus

A scope portion of an industrial video scope “IPLEX NX” (produced byOlympus Corporation) was inserted from an inspection hole (notillustrated in the drawing) in the side surface of the heat-treatingapparatus, a state of melt-adhesion in the apparatus was examined, andassessment was performed in accordance with the following criteria.

A: a level in which no melt-adhesion is observedB: a level in which melt-adhesion is slightly observed, but there is noproblem in the operationC: a level in which melt-adhesion is observed, but there is no problemin the operationD: a level in which melt-adhesion is observed, and the operation has tobe stopped for cleaning

The results of the above-described evaluation are presented in Table 2.

Examples 2 to 23 and Comparative Examples 1 to 5

Toner powder particles B1 were heat-treated in a manner akin to that inexample 1 except that the operation conditions of the heat-treatingapparatus were changed to conditions presented in Table 1. Further, theweight average particle diameter and the average circularity of theresulting heat-treated particles were measured and evaluated in a mannerakin to that in Example 1. The results are presented in Table 2.

Comparative Example 6

Toner powder particles B1 were heat-treated in a manner akin to that inexample 1 except that the humidity-adjusting unit was not connected tothe hot-air supplying unit and that the operation conditions of theheat-treating apparatus were changed to conditions presented in Table 1.Further, the weight average particle diameter and the averagecircularity of the resulting heat-treated particles were measured andevaluated. The results are presented in Table 2.

TABLE 1 Speed of Relative Hot-air conveying air humidity of Hot-airabsolute per powder- gas flowing Example/ relative Hot-air moistureAmount of particle in heat- Comparative humidity temperature content hotair supplying treating example (%) (° C.) (g/m³) (m³/min) unit (m/s)apparatus (%) Example 1 67.3 160.0 2085.0 35.0 8.0 90 Example 2 60.0165.0 2085.0 35.0 8.0 95 Example 3 53.7 170.0 2085.0 35.0 8.0 98 Example4 53.7 170.0 2085.0 35.0 3.0 98 Example 5 53.7 170.0 2085.0 35.0 12.0 98Example 6 53.7 170.0 2085.0 35.0 15.0 98 Example 7 53.7 170.0 2085.035.0 2.0 98 Example 8 53.7 170.0 2085.0 45.0 2.0 98 Example 9 53.7 170.02085.0 20.0 2.0 98 Example 10 53.7 170.0 2085.0 48.0 2.0 98 Example 1153.7 170.0 2085.0 15.0 2.0 98 Example 12 4.1 101.0 25.0 15.0 2.0 98Example 13 46.9 185.0 2500.0 15.0 2.0 98 Example 14 4.1 100.5 24.5 15.02.0 98 Example 15 42.8 190.0 2520.0 15.0 2.0 98 Example 16 4.0 100.524.0 15.0 2.0 98 Example 17 75.0 163.5 2520.0 15.0 2.0 98 Example 18 3.8102.0 24.0 15.0 2.0 98 Example 19 77.6 162.0 2520.0 15.0 2.0 98 Example20 78.0 200.0 5568.2 15.0 2.0 98 Example 21 3.8 100.0 22.4 15.0 2.0 98Example 22 80.0 200.0 5711.0 15.0 2.0 98 Example 23 3.0 100.0 17.7 15.02.0 98 Comparative 3.8 95.0 18.9 15.0 2.0 98 example 1 Comparative 78.0205.0 6110.2 15.0 2.0 98 example 2 Comparative 2.5 160.0 77.5 15.0 2.098 example 3 Comparative 85.0 160.0 2634.4 15.0 2.0 98 example 4Comparative 85.0 205.0 6658.5 15.0 2.0 98 example 5 Comparative 2.5 95.012.5 15.0 2.0 98 example 6

TABLE 2 D4 after average Evaluation Example/ heat circularity ofmelt-adhe- Evaluation Comparative treatment ΔD4 after heat sion insideof cohe- example (μm) (μm) treatment apparatus siveness Example 1 5.730.00 0.968 A A Example 2 5.75 0.02 0.968 A A Example 3 5.77 0.04 0.969 AA Example 4 5.79 0.06 0.969 A A Example 5 5.80 0.07 0.967 A A Example 65.82 0.09 0.966 A A Example 7 5.83 0.10 0.967 A B Example 8 5.85 0.120.967 A B Example 9 5.87 0.14 0.965 A B Example 0 5.90 0.17 0.966 B BExample 11 5.94 0.21 0.964 A C Example 12 5.95 0.22 0.962 A C Example 135.97 0.24 0.965 A C Example 14 5.98 0.25 0.962 B C Example 15 5.99 0.260.965 B C Example 16 6.00 0.27 0.962 B C Example 17 6.00 0.27 0.964 B CExample 18 6.00 0.27 0.962 C C Example 19 6.00 0.27 0.964 C C Example 206.01 0.28 0.966 C C Example 21 6.01 0.28 0.958 C C Example 22 6.02 0.290.966 C C Example 23 6.02 0.29 0.957 C C Comparative 6.05 0.32 0.955 C Dexample 1 Comparative 6.18 0.45 0.965 D D example 2 Comparative 6.100.37 0.964 D D example 3 Comparative 6.21 0.48 0.963 D D example 4Comparative 6.24 0.51 0.965 D D example 5 Comparative 6.30 0.57 0.954 DD example 6

While the present disclosure has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2021-192912 filed Nov. 29, 2021, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A method for manufacturing a toner comprising:supplying powder particles containing a binder resin via a plurality ofpowder-particle supplying units to a treating chamber, the treatingchamber comprising a cylindrical inner peripheral surface; heat treatingthe powder particles in the treating chamber by supplying hot air intothe treating chamber, wherein a temperature of the hot air supplied intothe treating chamber is 100.0° C. or higher and 200.0° C. or lower; andadjusting a humidity of the hot air so that a relative humidity of thehot air supplied into the treating chamber is 3.0% or more and 80.0% orless.
 2. The method for manufacturing a toner according to claim 1,wherein the relative humidity of the hot air supplied into the treatingchamber is 4.0% or more and 75.0% or less.
 3. The method formanufacturing a toner according to claim 1, wherein an absolute moisturecontent (g/m³) in the hot air supplied into the treating chamber is 25.0g/m³ or more and 2,500.0 g/m³ or less.
 4. The method for manufacturing atoner according to claim 1, wherein an amount of the hot air suppliedinto the treating chamber is 20.0 m³/min or more and 45.0 m³/min orless.
 5. The method for manufacturing a toner according to claim 1,wherein a speed of the conveying air per unit of the plurality ofpowder-particle supplying units is 3.0 m/s or more and 12.0 m/s or less.6. The method for manufacturing a toner according to claim 1, whereinheat treatment in the treating chamber is performed under gas flowinghaving a relative humidity of 95.0% or less.